The present invention relates to a firing furnace, and more particularly, to a resistance-heating firing furnace for firing a molded product of a ceramic material and a method for manufacturing a porous ceramic fired object using such a firing furnace.
A molded product of a ceramic material is typically fired in a resistance-heating firing furnace at a relatively high temperature. An example of a resistance-heating firing furnace is disclosed in JP-A 2002-193670. This firing furnace includes a plurality of rod heaters arranged in a firing chamber (muffle) for firing a molded product. A material having superior heat-resistance is used for the resistance-heating firing furnace to enable firing at high temperatures. In the conventional firing furnace, electric current is supplied to the rod heaters to generate heat. The radiation heat from the rod heaters heats and sinters the molded product in the firing chamber to manufacture a ceramic sinter.
A conventional resistance-heating firing furnace includes a power feeding unit for feeding power to a heater. As shown in FIG. 7, a power feeding unit 100 includes a connector 101 for connecting an electrode member 104, which is connected to an external power supply, to a heater 105, a fixing member 102 for covering the connector 101, and an insulative member 103 for electrically insulating the connector 101 and the fixing member 102. The firing furnace has a housing with an inner wall along which a heat insulative layer 106 is applied. In part of the heat insulative layer 106, a through hole 106a is formed to receive the power feeding unit 100. The fixing member 102 of the power feeding unit 100 is fitted to the through hole 106a. An insertion hole 107 is formed in the fixing member 102 for insertion of the connector 101. The insulative member 103, which is annular, is held between the wall of the insertion hole 107 and the connector 101 to electrically insulate the wall of the insertion hole and the connector 101. The contents of JP-A 2002-193670 are incorporated herein by reference in their entirety.